PRESENTATION
BROCHURE
ESSENTIAL G IDES ON CATTLE FARMING
Bovine Viral Diarrhoea (BVD) Francisco J. González Rodríguez
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ESSENTIAL GUIDES ON CATTLE FARMING
Bovine Viral Diarrhoea (BVD)
ESSENTIAL G IDES ON CATTLE FARMING
Bovine Viral Diarrhoea (BVD) Francisco J. González Rodríguez
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In the last decades, much research has been conducted on bovine viral diarrhoea (BVD), a disease which causes a variety of clinical signs as well as deaths, abortions and huge economic losses in the cattle industry worldwide. Despite the efforts to control BVD on farms, the virus has continued to spread and is still a concern for farmers and veterinary practitioners. This guide will provide readers with essential, practical and up-to-date knowledge to understand and fight the disease regardless of the farm’s production system. This guide has been written by Francisco J. González Rodríguez, an experienced beef and dairy cattle consultant with a special interest in bovine viral diseases and cattle management.
TARGET AUDIENCE: ✱ Production animal vets. Cattle ✱ Animal production technicians
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RETAIL PRICE
€35
FORMAT: 17 ×11 cm NUMBER OF PAGES: 84 NUMBER OF IMAGES: 50 BINDING: softcover, wire-o. ISBN: 978-84-16818-49-5
Author FRANCISCO J. GONZÁLEZ RODRÍGUEZ He graduated in biology and veterinary medicine from the Complutense University of Madrid (UCM, Spain), and holds a master’s degree in virology by the UCM. He works as an independent consultant in animal health and dairy and beef cattle management for several corporations in Spain, Italy and Portugal.
KEY FEATURES:
➜ Includes practical information to fight BVD regardless of the farm’s production system. ➜ Written by an experienced beef and dairy cattle consultant. ➜ Small, easy-to-handle format.
Presentation of the book In my mind, and for many years, the BVDVs have become the lying viruses. A lot of well documented knowledge has periodically shown the need for a deep review, forcing scientists, practitioners and even governments officials to change their thoughts about what BVDVs are, their impacts on animal health and production and the strategies they should employ to control their multiple manifestations and ways of transmission. Among these changes, there is one thing, at last, standing: BVDVs are considered amongst the major threats to cattle production and welfare. When BVDVs are around, each case is highly unique, taking into account the multiple specific scenarios that the interaction between the viruses, the farm, and the social, economic, and regulatory environments can generate. With such a controversial agent, a manual cannot be a simple do’s and don’ts guide. This approach would lead, in many cases, to misconceptions, no way out lanes and costly infructuous decisions. My objective is to provide a clear, up-to-date, evidence-based panorama where any practitioner could evaluate the situation of each customer and be able to take and recommend the best specific plan of actions to prevent or control the BVDV menace. My hope is that, when you walk along this guide, you will find some ideas to apply, some ideas to adapt, some ideas to rethink and some questions to answer by yourself when facing the BVDVs in your daily work whatever you focus is: dairy, beef of feedlots. Francisco J. González Rodríguez
Bovine Viral Diarrhoea (BVD)
The author Francisco J. González Rodríguez Francisco González graduated in biology and veterinary medicine from the Complutense University of Madrid (UCM). He also holds a master’s degree in business administration by the Madrid Business School/Houston University (Repsol-Honda Award for Excellence in Marketing) and a master’s degree in virology by the UCM.
hkeita/shutterstock.com
He currently works as an independent consultant in animal health and dairy and beef cattle management for several corporations in Spain, Italy and Portugal, and is responsible for marketing, training and technical activities such as epidemiological studies and clinical trials (supervision and execution). Formerly he worked for many years for the pharmaceutical industry as product manager in the livestock sector (including dairy and beef cattle) where he was involved in biological and medical products development, field research and training. He worked on the launch and follow-up of several drug products in both the pig and cattle industry. He has attended many courses in animal health, sales, marketing, negotiation, computing and leadership.
Table of contents 1. Why BVDVs?
5. Economic impact
History, taxonomy, and structure Genetic variability and implications for diagnosis and disease control Biotypes and biological importance
Effects on reproduction Endemic infection BVD, heifers, and beef farms Economic models
6. Diagnosis
2. Epidemiology Routes of transmission and biosecurity Animal–animal transmission Artificial insemination (AI) and embryo transfer (ET) Iatrogenesis Fomites and insects
PI animals
Epidemiological tools Tools for individual diagnosis Direct tests Indirect tests
Practical interpretation of results
7. Control strategies Biosecurity and biocontainment
3. Immune system The immune response to horizontal and vertical infections Immunosuppression Immune response to vaccination Humoral immune response Cellular immune response
Finishing farm
The Trojan cow Monitoring Vaccination
8. Bibliography
Cross-protection and vaccine failure Duration of immunity
Tips for proper vaccination
4. Clinical and subclinical forms Pathogenesis Clinical signs and lesions BVDV and bovine respiratory disease Transplacental infections Mucosal disease Chronic diarrhoea Haemorrhagic syndrome Lesions commonly observed upon field necropsy Subclinical BVD
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ESSENTIAL G IDES ON CATTLE FARMING
Bovine Viral Diarrhoea (BVD) Francisco J. González Rodríguez
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Epidemiology
Bovine Viral Diarrhoea (BVD)
The prevalence of infection and of PI animals varies considerably depending on the location studied. Therefore, to eliminate or control BVDVs, or to keep a farm virus-free, it is important to understand and effectively address the corresponding environmental risks and routes of transmission.
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1 study 2–4 studies ≥ 5 studies Figure 1. Global distribution of BVDVs.
Unpublished Published
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EPIDEMIOLOGY
Routes of transmission and biosecurity
Most common route (> 90 %)
Least common route (< 10 %)
Susceptible pregnant cow (non-PI) infected with BVDV between months 1.5 and 4 of pregnancy
PI cow becomes pregnant
Animal–animal transmission The main route of transmission is direct contact with an infected animal, via its secretions (saliva, mucus, urine, faeces, semen, milk, colostrum, etc.) or blood.
Figure 2. Vertical routes of BVDV transmission.
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BVDV of any origin
Results in PI calf with BVDV
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Epidemiology
Bovine Viral Diarrhoea (BVD)
Animals with an acute infection can shed viral particles for days or weeks (ranging from 24 hours to less than 20 days), with the exception of the following scenarios: ◗ Bulls with a prolonged testicular infection, which can shed viral particles in semen for months. ◗ Latent infections with the capacity for intermittent reactivation: CP strains have been detected in nasal secretions and tissues long after the elimination of viraemia.
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Figure 3. Housing conditions are of major importance in the spread of infection. Pens with large numbers of animals are more likely to harbour PI animals, and viral spread is favoured by high population densities, fences that allow nose-to-nose contact, feeders or drinkers shared by several stalls, and the use of unchecked bulls for breeding.
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EPIDEMIOLOGY
Some diseases that can be transmitted via colostrum: ◗ ◗ ◗ ◗ ◗ ◗ ◗ ◗ ◗ ◗
BVD. Campylobacteriosis. Colibacillary enteritis. Leptospirosis. Leucosis. Listeriosis. Infectious mastitis. Mycoplasmosis. Salmonellosis. Tuberculosis and paratuberculosis.
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Figure 4. Feeding waste milk to calves is a risky practice. If done, milk should be pasteurised to prevent the spread of BVDVs and other pathogens. In colostrum the presence of anti-BVDV antibodies can limit viral infectivity, except if the mother is a PI animal.
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Epidemiology
Bovine Viral Diarrhoea (BVD)
Artificial insemination (AI) and embryo transfer (ET) Both PI bulls and bulls with persistent testicular infection excrete viral particles in semen that can infect unprotected animals and cause viraemia, clinical infection, embryonic or foetal death, and the birth of PI calves. Monitoring carried out in AI centres significantly limits these outcomes.
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Figure 5. Infections that develop following embryo transfer can have numerous origins, e.g. the donor cow, recipient cow, semen, or washing serum. All components of this process should be evaluated to minimise the risk of BVDV infection.
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EPIDEMIOLOGY
Iatrogenesis BVDVs can be transmitted via rectal palpation when the same glove is used to palpate several cows after palpation of a PI animal. Viruses can also be transmitted when the same needle is used in various animals: BVDVs can survive on needles for up to 3 days after use in a PI animal.
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Figure 6. BVDV control is dependent on maintaining strict hygiene practices when handling animals.
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Epidemiology
Bovine Viral Diarrhoea (BVD)
Fomites and insects The virus can be spread by tractors or other vehicles with contaminaed material on their wheels, as well as by trucks used for cadaver removal. These vehicles should be kept away from the farm population. Blood-sucking flies can infect susceptible animals after feeding on PI animals. Hygiene and disinfestation of farm facilities are essential for BVDV control.
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Figure 7. Transport of feed, cadavers, and live animals constitutes an important potential source of viral infection.
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EPIDEMIOLOGY
PI animals Animals infected with a NCP strain in utero before 120â&#x20AC;&#x201C;150 days post-conception assimilate the virus and are unable to develop an immune response against the infecting strain. These animals spread large amounts of virus throughout their lives, although in some cases this viral shedding may be intermittent. In normal conditions, an animal with a transient infection has a very limited ability to spread infection (R0 <1). For PI animals, R0 values increase to >35, and potentially to +â&#x2C6;&#x17E;. R0 represents the number of new infections that a case can generate within a susceptible population. An R0 <1 implies that the infection is self-limiting. R0 >35 indicates that a single infected animal in a susceptible population can transmit the infection to at least another 35 animals.
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While the removal of PI animals is essential for a successful BVDV control protocol, these animals are not always easily identified.
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The publishing strength of Grupo AsĂs Editorial Servet, a division of Grupo AsĂs, has become one of the reference publishing companies in the veterinary sector worldwide. More than 15 years of experience in the publishing of contents about veterinary medicine guarantees the quality of its work. With a wide national and international distribution, the books in its catalogue are present in many different countries and have been translated into nine languages to date: English, French, Portuguese, German, Italian, Turkish, Japanese, Russian and Chinese. Its identifying characteristic is a large multidisciplinary team formed by doctors and graduates in Veterinary Medicine and Fine Arts, and specialised designers with a great knowledge of the sector in which they work. Every book is subject to thorough technical and linguistic reviews and analyses, which allow the creation of works with a unique design and excellent contents. Servet works with the most renowned national and international authors to include the topics most demanded by veterinary surgeons in its catalogue. In addition to its own works, Servet also prepares books for companies and the main multinational companies in the sector are among its clients.
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